You are able to successfully login to VIDM but the UI elements are blank. The navigation elements (Dashboard, Users & Groups, Catalog, Identity & Access Management, Appliance Settings, Roles) are present, but clicking on them might not lead to any data.
VMware Identity Manager 3.3.x
This happens if the VIDM Certificates are expired causing browser to not trust it and refuses to load
To verify the certificate expiry from a browser, follow these steps:
Replace the expired certificate using steps from https://docs.vmware.com/en/VMware-Aria-Suite-Lifecycle/8.18/lifecycle-install-upgrade-manage/GUID-E6243CDE-5CEA-4ABA-B6A9-71E6B58D0459.html
Note : If you are replacing a cluster setup you should also replace the certificates in the load balancer. Find the steps to replace the load balancer certificates from https://knowledge.broadcom.com/external/article?legacyId=94095 , Follow section 3. Certificate missing in the load balancer.